This invention relates to an exchangeable gun arm welding gun in which a gun arm is detachably fitted to an arm holder, and to a gun arm exchange apparatus therefor.
As disclosed in Japanese Unexamined Utility Model Registration Application Publication, Jikkai Sho 49-14738, a welding gun is known having a shaft portion on the tail end of a gun arm inserted into a hole provided in the arm holder fitted to the gun body. The shaft portion is fastened securely to the arm holder by tightening a bolt inserted in a direction perpendicular to the hole.
In this known welding gun, the fastening bolt can be loosened for exchanging of the gun arm, but it has to be loosened and tightened each time the gun arm is exchanged, so that it would take considerable labor and time to carry out the exchange operation.
In view of the above-noted problem, the object of the present invention is to provide a welding gun that permits the gun arm to be exchanged or replaced with another one by easy one-touch operations without use of a fastening bolt, and further to provide a gun arm exchange apparatus that can carry out an automatic gun arm exchange operation.